In certain aspects, the present invention may be regarded as an improvement over the ROLLER APPLICATORS disclosed in U.S. Pat. No. 3,103,689, issued Sep. 17, 1963 to Bernard Borisof. Such patent discloses a roller applicator comprising a body including a bowl for receiving wax or the like to be melted and maintained in a molten state. The molten wax is supplied to an applicator roller which is rotatably mounted on a lower portion of the bowl. The roller acts as a closure for an opening formed in the lower portion of the bowl, so that the molten wax flows through the opening to the roller. An appropriate seal is provided around the opening, between the roller and the bowl, to permit rotation of the roller while preventing any leakage of molten wax. An electrical resistance heating element is provided in the bowl for melting the wax and maintaining it in a molten state. The heating element also heats the roller so that the wax remains molten on the surface of the roller. Electrical power is supplied to the heating element by an electrical power cord which may be plugged into an electrical outlet, adapted to supply electrical power, usually at about 120 volts, 60 Hertz alternating current.
The wax applicator of the above mentioned Borisof patent has a convenient handle, projecting from the bowl, whereby the user may apply a stripe of molten wax to the desired paper or other surface by pressing the roller against the desired surface and causing the roller to roll along such surface. The roller receives the molten wax from the bowl and transfers the wax to the desired surface, where the wax solidifies and provides an adhesive coating, whereby the paper or other material may be adhered to another surface, which may be on another piece of paper, a wall, a window or the like.
In the wax applicator of the Borisof patent, the electrical resistance heating element is energized continuously with electrical power. The wattage of the heating element is selected so that the wax will be melted, without too much delay, and will be maintained in a molten state, but will not be excessively overheated during normal service, when the wax applicator is used with a fair degree of frequency. The selection of the wattage must necessarily be a compromise between the conflicting problems of overly slow melting of the wax, if the wattage is too low, and overheating of the wax, if the wattage is too great. If the wattage is selected on the low side, to prevent overheating of the molten wax, the initial heating of the wax will be overly slow, involving an inconvenient delay. If the wattage is selected on the high side, to achieve quicker initial melting of the wax, the molten wax may be overheated sufficiently to scorch or otherwise damage the molten wax. Overheating may cause the wax to become discolored or darkened.